In uplink transmission, that is, in a case where a user equipment functions as a transmitter, various methods for controlling power such that the capacity of a battery is increased or power consumption of the user equipment is decreased so as to increase the duration of the user equipment have been suggested. Examples of the methods for controlling the power may include a discontinuous transmission scheme.
The discontinuous transmission scheme may be, for example, a method for instantaneously reducing a data transmission output or setting a silent state when a voice signal is not transmitted in a mobile phone or a portable wireless phone. When two persons talk over phone, a talk time of each of the two persons is equal to or less than a half of a total talk time. Thus, if connection to a transmitter is established only during a voice input time, a transmission time may be reduced to 50% or less. Accordingly, advantages including conservation of battery power, reduction of a load of a transmitter amplifier, and channel sharing with another signal in view of time division multiplexing (TDM) can be obtained.